linux-kernel - Re: [PATCH v2] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel

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Message-ID: <20190402110635.GC1555@localhost.localdomain>
Date:   Tue, 2 Apr 2019 19:06:36 +0800
From:   Chao Fan <fanc.fnst@...fujitsu.com>
To:     Junichi Nomura <j-nomura@...jp.nec.com>
CC:     Borislav Petkov <bp@...en8.de>, "bhe@...hat.com" <bhe@...hat.com>,
        Dave Young <dyoung@...hat.com>,
        "kasong@...hat.com" <kasong@...hat.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "kexec@...ts.infradead.org" <kexec@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] x86/boot: Use efi_setup_data for searching RSDP on
 kexec-ed kernel

On Tue, Apr 02, 2019 at 09:53:51AM +0000, Junichi Nomura wrote:
>On Tue, Apr 02, 2019 at 05:41:49PM +0800, Chao Fan wrote:
>> [   77.989030] kexec_core: Starting new kernel
>> early console in extract_kernel
>> input_data: 0x000000017f6033b1
>> input_len: 0x00000000008412d4
>> output: 0x000000017e000000
>> output_len: 0x0000000001e15844
>> kernel_total_size: 0x0000000001e2c000
>> trampoline_32bit: 0x000000000009d000
>> booted via startup_64()
>> 
>> 
>> Physical KASLR disabled: no suitable memory region!
>> ------
>> 
>> I am not sure whether I have done the right test.
>> This guest is booted from EFI. Here we can see the kexeced kernel
>> has completed the compressed boot stage. So I think your PATCH works.
>
>Thanks for testing.  If your test bed doesn't boot even with the patch,
>you could check what was found as RSDP with a debug patch like below.

Oh no, it booted. I just put the compressed stag log.

Thanks,
Chao Fan

>
>diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
>--- a/arch/x86/boot/compressed/misc.c
>+++ b/arch/x86/boot/compressed/misc.c
>@@ -379,6 +379,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
> 	debug_putaddr(output);
> 	debug_putaddr(output_len);
> 	debug_putaddr(kernel_total_size);
>+	debug_putaddr(boot_params->acpi_rsdp_addr);
> 
> #ifdef CONFIG_X86_64
> 	/* Report address of 32-bit trampoline */
>
>